Dark boy and Mama's boy!!!!!!!

[XcrossD]

Only these 2 secrets and daddy longlegs left. Just grind or something? How do you get those 2 without some luck? T_T

2012/11/19 UPDATE: Since I posted this I have never gotten Emperor card. Judging from most people say Emperor card is pretty much essential. I play several runs per day but never got Emperor card :( at the brink of insanity now

EDIT:
Tips so far (for those looking to do the same)
Wiki - http://bindingofisaac.wikia.com/wiki/No_Damage_Achievement_Guide
Challenges suggested - Large marge, Isaac was good today, Spider boy, Doctor's revenge

[Flopple]

Daddy Longlegs will unlock after you beat him, but he's an alternate boss, and a rare one at that. I'm pretty sure you find him in Necropolis but I could be wrong. As for the other two I haven't unlocked either of em yet, but I'd say you'd just have to be super ♥♥♥♥♥♥ cautious.

[BadEvilWrong]

Mom and Mom's Heart get OHKO'd by using a bible. Emperor cards are good for getting to the boss rooms, especially with XL floors.

[XcrossD]

引用自 BadEvilWrong：

Mom and Mom's Heart get OHKO'd by using a bible. Emperor cards are good for getting to the boss rooms, especially with XL floors.

This combo doesn't appear very often T_T

[99seconds]

Strangely enough, I got Mama's Boy before I've even got the one for beating the Basement without damage. (-_-')

Also, you say that Emperor cards + XL floors is extremely uncommon? Eliminate one variable- Play the Large Marge Challenge Run.

[TwerknlikeMiley]

i also made a thread like this try 'the shovel'

[XcrossD]

引用自 ieatdinosaurs：

i also made a thread like this try 'the shovel'

FML once I got the shovel and then there was the curse of the labyrinth =.= and then another time I got hit before I got technology 1 + polyphemus combo and never got hit again throughout that level =.=

[Arsenic Candy!!!]

The Wiki is really helpful for this.

http://bindingofisaac.wikia.com/wiki/No_Damage_Achievement_Guide

[XcrossD]

引用自 Arsenic Candy!!!：

The Wiki is really helpful for this.

http://bindingofisaac.wikia.com/wiki/No_Damage_Achievement_Guide

Yeah, really helpful I agree, but I have no luck :(

[hoboshoe]

i remember when i was new to BoI i got technology+tripe shot+ moms eye, and i still managed not to kill mom

[SADevil]

引用自 99seconds：

Strangely enough, I got Mama's Boy before I've even got the one for beating the Basement without damage. (-_-')

I'm too! I have Basement Boy and Mama's Boy (found The Shovel and The Emperor Tarot card), then won It Lives (or Mom's Heart, don't remember) without taking damage. And now can't get other two achievements...

[Azuri Caelum]

I got Mama's Boy by literally getting an XL floor and finding the boss rooms within 3 screens from the entrance. I had a standard run otherwise.

[XcrossD]

引用自 Aardvark Syndrome：

I got Mama's Boy by literally getting an XL floor and finding the boss rooms within 3 screens from the entrance. I had a standard run otherwise.

Did you have map or compass that time?

[Azuri Caelum]

I don't remember. I may or may not have had the compass, but I know I didn't have the map.

[XcrossD]

引用自 Aardvark Syndrome：

I don't remember. I may or may not have had the compass, but I know I didn't have the map.

So it's pure luck eh? The randomness is really screwing me over :/

[SADevil]

Good advise from Wiki for unlocking "... boys" achievements is to trying it in challenge "Isaac was good today" due to having flying ability and better stats from the begining. If you select Judas you will have red tears even from start! I achieved Dark Boy this way with one attempt but I was lucky to obtain The Emperor tarot card to teleport to Mom, also I became Guppy very early. And had Compass...
Yeah, randomness sometimes driving me crazy too.